Device for conversion of frequencies



Feb. 20, 1951 E. ToRcHEUx 2,542,732

DEVICE FOR CONVERSON'OF FREQUENCIES Filed May 3, 1945 7 Sheets-Sheet 1DEVICE FOR CONVERSION OF FREQUENCIES Filed May 5, 1945 7 Sheets-Sheet 2I l A@ e 'la D l @I UO S, So

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INVENTOR ENTS b. 20, 1951 E. ToRcHEux 2,542,732

DEVICE FOR CONVERSION OF FREQUENCIES Filed May 3, 1945 x 7 Sheets-Sheet3 @mai/MMM.

ATTORNEYS Feb. 20, 1951 E. ToRcHEUx DEVICE FOR CONVERSION oF-FREQUENCIES 'r sheets-sheet 4 Filed May 3, 1945 In v Mq, 2, 95% E.TORCHEUX I DEVICE FOR CONVERSION 0F FREQUENCIES Filed may 5 1945'smets-snt s www? BMCKE BMC/m wat@ @Lma @lam 27am; 9am .vom mad 15d iMMM @ma Kc. afan/fc. fwn/Ya. i 'Hanke 250m;

K w 50 /fc Arrows/fm' Feb@ 2, w51 E. "mmm-umm DEVICE FOR CONVERSION OFFREQUENCIES Filed may 5, 1945 7 S'aezS-Sheet` 6 mmf/vra@ EM/.f 75m/750%Afro/wim' Filed May 3, 1945 E. TECH-MIEUX DEVICE FOR CONVERSION 0FFREQUENGIES '7 Sheets-Sheet 7 Patented Feb. 20, 1.951

DEVICE FOR CONVERSION OF FREQUENCIES Emile Torcheux, Paris, France,assignor to Societe Franaise Radio Electrique, a corporation of FranceApplication May 3, 1945, Serial No. 591,714 In France January 26, 1940Section 1, Public Law 690, August 8, 1946 Patent expires January 26.1960 (Cl. Z50- 40) 4 Claims.

This invention relates to devices for conversion of frequencies such asthose used in the transmission or reception of radio-electric waves.

The construction of transmitting and receiving 2 range of frequenciesF1.` The device acts on the well known principle of the change offrequency and makesuse of members and devices known per se ashereinafter indicated, the invention apparatus capable of operating onany frequen- 5 consisting essentially of the combination of three ciesover their entire range under conditions of elements as follows: greatStability and precision of adjustment f l. At least one frequencychanger selector comthe wave transmitted or received is of greatinprising, es known per Se, et least one lter ee,- terest not only withrespect to the reliability of pabie of being tuned to the frequencies F1by a the communication but also as t0 the quality 0f l0 tuning systemwith linear variation of frequency. reception and rapidity ofestablishing a connec- 2. At least one generator to produce, in amantion. These conditions are of particular impclner known per se, atleast two substitutable fixed tance in communications in which the Wavefrequencies Fq selected in such a manner that lengths used arefrequently changed and where it in the frequency changer the equation:is desired to tune to a predetermined Wavelength l5 and establishimmediate contact with the best |F1"F 1l=F possible ratio 0f signal t0parasitic ncise- In can be satisfied by using one of the frequenciesthis connection it may be remarked that an ap- Fn whatever may be thevalue of F1 under conparatus as visualised in the present inventionsideyetien must be capable of being regulated in advance on 3. A systemof connection ensuring a demulto a given WaVelength and be capable 0f atOnce tiplication of movement between the member receiving an emiSSicnhaving this Wavelength; controlling the tuning system on the frequenciesthe recepticn must take Place under the best Fo and the membercontrolling the tuning sysconditions of the ratio between useful signaltem on the frequencies F1, in such a manner t0 parasite noises, that isto say, the receiver 25 that there corresponds to every variation offremust be eXactly regulated t0 the Wavelength t0 quency on thefrequencies Fo the same variation be received. in absolute value on thefrequencies F1, the said In most cases. the precision and Stability aresystem of connection comprising furthermore a eXDressed as a percentage0f the frequency transdisplacement device effective to modify,indemitted. Means are knOWn fOr Obtaining Very pendently of the movementof the member conereat stability in the Case 0f a particular fretrouingthe tuning syste-rn on the frequencies F0 (luency 0r in the Vicinity ofthis frequency, but and conjointly with the placing in service of thethere is then excluded the possibility of Varying fixed frequency Fqutilised in the change of frethe frequency over a continuous andextended quency, the member controlling the tuning sysrange. 35 tem onthe frequencies F1 to a position of ad- Now what it is required toobtain is that with jugement; this movementy defined by the disthe saineSysten 0f COTnInunicatiOn, Whether this placement effected by the membercontrolling the be in Short Waves 0r Ineclilln WaVeS, the band 0C-tuning system on the frequencies F1 from its inicupied presents the SameabsolutJe Value; for eX- tial position (i. e. that from which thefrequencies ample, in telephony a Value 0f 6 kcand in teleg- 40 F1 aretraversed) to its position of adjustment, raphy a Value limited by thespeed 0f manipllbeing such that when the tuning system on the lation.frequencies F1 is tuned to the frequency corre- The device forming theobject 0f the Present sponding to the said position of adjustment, theinvention enables transmitters and receivers to System of tuning eni-,he frequencies F0 is tuned be produced having the above qualities forany to one of the limit frequencies of the range of frequency within theentire range for which the frequencies Fo. transmitter or receiver isconstructed. The invention will now be further described This deviceapplied to a receiver serves to bring with reference to the Figure la,of the accomthe various frequencies F1 of an extended range panyingdrawings, in which the device according into closer limits of a lowerrange of frequencies to the invention is represented diagrammatically F0covered in a continuous manner by a tuning as applied by Way of exampleto a receiver and system with linear variation of frequency; apascomprising only one frequency changer stage. plied to a transmitter, itserves on the contrary In such a device it is a question of bringing theto bring the various frequencies F0 of a restricted frequencies F1 of aWide range extending from range into more extended limits of a higherF10 to F11 into the narrower limits F00, F01 of a lower range offrequencies Fo covered in a continuous manner by a tuning system withlinear variation of frequency. This tuning system, represented by Co,has for its object to select the frequency Fo in the frequency selectorSo, and it is controlled by an actuating member Un the displacement aoof which is connected to the frequency Fo by the linear rule:

in which K and o are constants.

The device comprises in combination, in accordance with the foregoinggeneral statement of invention:

1. A frequency changer selector (S1-M 1) comprising at least one lteradapted to be tuned on the frequencies F1 by a tuning system with linearvariation of frequency. This tuning system, represented by C1 on Figurela, is controlled by a controlling member U1 the displacement a1 ofwhich is connected to the frequency F1 by the linear rule:

in which K1 and 181 are constants.

2. A generator G producing at least two substitutable fixed frequencies.These fixed frequencies, any one of which will be indicated by Fq, areselected in such a manner that in the frequency changer M1 the equation:

|F1-Fl=Fo (3) may be satisfied by using one of the frequencies Fq,whatever may be the value of F1 under consideration.

The Equation 3 may be set out in the following algebraical form:

F1-Fq=eF0 (3') by assuming that:

e=+1when F1 F 1 and e=l when F1 F I (4) The xed frequencies will beobtained, for example, by means of one or more quartz oscillators inorder to ensure a great stability of frequency.

3. A system of connection Lensuring a demultiplication of movement asbetween the control member Un of the tuning system Co and the controlmember U1 of the tuning system C1, in such a manner that therecorresponds to every variation of frequency on the frequencies Fo thesame variation in absolue value on the frequencies F1.

It is thus necessary to have:

dF1=edFo (5) The value of E is given by the Equation 4 since theEquation 3 must be satisfied at the same time as Equation 5.

Let us indicate by m the ratio of demultiplication between therespective displacements dan and dm of U0 and U1, there is given:

da1=m.dao (6) From the Equations 1, 2, 5 and 6, there is deduced 4thevalue of m' as follows:

The system of connection L comprises, intel' alia, a displacement deviceD effective to modify 'the adjustment of U1 independently of themovement of Un. This adjustment is dened by the displacement necessaryto cause a1 to pass from its vinitial value 111 corresponding to theinitial frequency F1' from which the range of frequencies F1 is passedthrough, to its adjustment value a1Y to which the frequency F17corresponds. There is thus obtained by definition of the ad- J'ustment:l

Y 0l1nl 0l10 with, according to the Equation 2,

Taking this equation into consideration (8) becomes:

and

in which according to the invention, F0 is equal to one of the limitfrequencies of the range of frequencies Fo, that is to say either to F00or F01. This relation permits of determining ry as soon as the directionhas been fixed in which the frequencies F1 are passed through. If, forexample, the direction is of increasing frequencies, on the one handF1=F1U and on the other hand if the lower limit F00 be taken for For,the frequencies Fo can only increase, that is to say, there is given:e=ll according to the Equation (5): on the contrary, if the upper limitF01 is taken for Fol, the frequencies Fo can only decrease that is tosay, there is given: e=-l. There are consequently only two possiblesolutions, for with The device according to the invention permits ofobtaining simultaneously the precise tuning of the two selectors So andS1 at the same time that it permits of covering extensive ranges withvery few electric contacts, due to the fact that the passage from onesection of frequencies to the following one takes place by changing thezone used of the control member of the tuning system. This reduction inthe number of the electric contacts is still further accentuated whenthere are placed in cascade several similar devices. On the other hand,the device is particularly well adapted for the use of the twofrequencies which can be obtained in the change of frequency (these twofrequencies are given by the Equation 3 according to the Value of e) Inthis case, it is obviously necessary to provide means for reversing theratio of demultiplication between the members U0 and U1. These means mayconsist of mechanical devices such as connecting rods or eccentrics orelectrical devices such as condensers with two symmetrical stators withcommutation or a set of two similar condensers of connected and reversedmovement, with commutation.

The system of connection is carried out by means of a train of gearingwith differential movement permitting, by displacement of the crownwheel of the gear carrying the satellites, of shifting the controlmember U1 with respect to the control member Uu without modifying theratio of demultiplication between these two members.

An advantageous arrangement is realisable when the range of frequenciesF covers the frequencies f to 3f (f being a definite number ofkilocycles) and the range of frequencies F1 covers the frequencies from3f to 91. Thus in this case, with two xed frequencies only, equalrespectively to f and 7j, all the frequencies F1 can be brought into therange of frequencies Fo by using as the connecting system a system ofgearing with diflierential movement having a ratio of 1/3 and comprisingfour positions of adjustment.

In general, the range to be transposed is very extended, it is thentransposed by successive stages by the aid of devices similar to thatdecribed, placed in cascade. In this the ranges to be transposed isdecomposed into intermediate ranges of decreasing extent in such amanner as to terminate finally at the range of frequencies Fo. It islater on indicated, by way of example, how it is possible to rise fromthe range of frequencies Fo to a range of frequencies Fn of any rank byemploying the decomposition termed with base 3. In case of thereception, the frequencies Fo varying from f to 3f arise from a firstfrequency change selector receiving the frequencies F1 variable from 3fto 9j and operating with two substitutable xed frequencies 5f and 7j,the frequencies F1 arising themselves from a second frequency changerselector receiving the frequencies F2 variable from 321 to 3(2+1)f andoperating with two substitutable xed frequencies 5 S(21 f and 7 3 21)f,the frequencies F2 from a third frequency changer selector receiving thefrequencies F3 variable from 33 to 3 3+Uf and operating with twosubstitutable fixed frequencies 5 3 3Uf and 7 3 31)j, and so on, thefrequencies F11-1 variable from 311-11 to 3f"1+1f arising from an nthfrequency changer selector receiving the frequencies Fn variable fromSuf to 3 11+Uf and operating with two substitutable fixed frequencies 53f11f and 7 3n1f.

The base 3 is particularly advantageous because on the one hand itallows the simplification of the mechanism and on the other it ensuresprotection against image waves, against the waves having the value ofthe frequencies resulting from the successive transpositions and againstthe reinjection of the heterodyne in the aerial.

Other distributions of the intermediate ranges are, however, possible.For example, the frequencies F0 still extending from f to 3f, the rstfrequency changer selector covers the frequencies from 4f to 12j andoperates with two fixed frequencies 'if and 91, the second frequencychanger selector covers the frequencies from 161 to 48j and operateswith two fixed frequencies 28j and 35j, the third frequency changerselector covers the frequencies from 64] to 192f and operates with thefixed frequencies 112 and 144i, and so on.

It would also be possible to start from a different range F0 extending,for example, from 2f to 4f. There might then be used a first selectorcovering the frequencies from 12j to 24f and operating with thesubstitutable fixed frequencies l6f, 181e and 20j, a second frequencychanger selector covering the frequencies from 72j to 144i and operatingwith the substitutable fixed frequencies 96j, 108f and 1201, and so on.

When the receiver operates on the heterodyne principle, the frequenciesFo are themselves made to beat with the variable frequency of theheterodyne, according to known practice. Where the frequencies F0 extendfrom j to 3j, there is used a heterodyne giving the frequencies from 3/2f to 5/21, in such a manner as to bring all the frequencies F0 to thefrequency f/2 of the stage of mean frequency.

By placing in service successively all the frequency changer selectors,it would be possible to successively cover the range of frequencies F1,the range of frequencies F2, the range of frequencies Fs, etc. As thefrequencies F0 can also be received directly, it will be seen that therecan be covered in this way a very extended range starting from thesmallest value of Fo and extending up to the greatest value of Fn.

An indicator device of the frequency Fn, on which the apparatus isregulated, is actuated on the one hand, from the shaft U (see Figure 1a)ensuring the simultaneous drive of the driving members U0 U1, U2 U11 andon the other hand, from the section handle T (or combiner) operatingconjointly the regulation of the displacement device or devices and theplacing into service of the fixed frequency or frequencies.

By reason of the linearity of frequency of the tuning systems, theindicator device indicates in a general way angles proportional to thefrequencies. It may, therefore, take the form of a revolution counterthe unit column of which is driven from the tuning knob (controlling theshaft U) and the hundreds or tens column by the combiner, if necessarythrough the intermediary of a system of differential gears. Thepossibility is thus given of obtaining directly the indication of thefrequency in kilocycles and covering the whole range dealt with by theaid of two means of control only, the tuning knob and the combiner. Y

Naturally, the device applies equally to emission as to reception, it issucient, according to known practice, to change the direction ofamplification and to consider as transmitted wave, the wave previouslyconsidered as received wave.

There will now be described, with reference to the accompanying drawingsand by way of example only, one method of carrying out theabovedescribed system, and in the description of this method, there willbe indicated various constructional forms for certain of the members orelements entering into the constitution of the system.

In the drawings referred to,

Figure 1 shows the wiring schematic of part of a receiver according tothe invention.

Figure la shows a simplified diagram of the essential parts of theembodiment of the invention.

Fig. 2 is a perspective view of part of the operating mechanismindicated diagrammatically in Fig. 1;

Figs. 3 and 4 are diagrammatic side elevations of parts of Fig. 2 indifferent operative positions;

Fig. 5 shows a general view of the mechanism of one embodiment of theinvention;

Figs. 6 and 7 show diagrammatically how to divide and operate anembodiment of the invention shown by way of example;

Figs. 8 and 9 show in perspective and partly diagrammatically somefurther mechanical details and associated wiring schematics; and

Fig. 10 shows a perspective view of a coordinating mechanism foroperating a device according to the'invention.

The receiver according. to the invention shown in Fig. l comprises thefollowing elements:

(i) A first filter changer block I of range comprised between the limits250-75() kilocycles, having two pre-selector circuits '2 and 3, anamplifier valve a tuned circuit y and a mixer Valve 6;

(ii) A heterodyne 'I of range 375-625 kilocycles, as stable as possiblein comparison with the temperature and controlled mechanically withprecision; this heterodyne excites the modulator electrode of the valveB of the preceding block, in suchY manner that at the outlet of thisblock there is collected a xed frequency or very stable mean frequencyof 125 kc.;

(iii) A mean frequency block 8 comprising (a) a narrow pass-band filter9 regulated to allow the passage simply of the frequency 125 kilocyclesand the immediately adjacent frequencies with variable selectivity and(b) a mean frequency amplier with two valves I and a beat mixer valveII;

(iv) A mean frequency heterodyne I2 of 127 kilocycles, and

(V) An anti-fading detector block I3 and low frequency amplier.

This combination of elements, acted upon by an aerial I G, in the firstposition of a commutator I5, ensures the reception of the rst sub-rangecomprising the frequencies from 250 to 750 kilocycles.

A second sub-range of 750 to 2500 kilocycles is received by the additionto the preceding elements of:

A second filter-changer block I6 comprising two pre-selector circuitsI'I and I8, an amplifier valve I9, two circuits 20 and a mixer valve 2IA heterodyne 22 of the two xed frequencies 1250 and 1750 kilocyclesproduced by quartz oscillators, with a commutator 23, for placing intooperation the one or the other frequency.

The total extent of the range, from 250 to 2500 kilocycles, is dividedinto 9 equal sections, each extending-over 250 kilocycles as shown inthe table below, the said table supplying in a general way the essentialindications as to the positions and the manipulations of the members(adjustment of the condensers of selector circuits and heterodyne,direction of rotation ofthe said condensers, quartz oscillator used onthe heterodyne) corresponding to each of the said sections.

8, different arrangements characteristic of the system. Thus, for thesection 250-500 the first high frequency block is utilised in the extentof this sub-range, the displacement or adjustment of the '1 condensersof the selector circuits is zero, the direction of the said condensersis forward, the direction of rotation of the condenser of the'heterodyneassociated with the first block (heterodyne 1) is also forward, thesecond high frequency block isnot in operation and the position of the'aerial commutator I5 is suchthat the aerial is tapped at the inletterminals of the rst high frequency block.

In the case of the section 50G-750, there are the same arrangementsexcept that the zoner of utilisationof the rst block HF" is that of 500to' 750 kilocycles, the filter condensers being displaced by 90;

For thev section '750-1000l the lst block HF is utilised in its 250-500range (traversed in the descending direction-500-250) the filtercondensers being displaced by 90", their direction of rotation, as alsothat of the heterodyne condenser, being in the reverse sense, the 2ndblock HF is utilised in its range 750-1000, the filter condensers inputof the 1st block HF.

The data of the table, for the other sections, will be self-evident inthe light of the above explanations. l

The manipulation of the different members is ensured by means of twohandles, one controlling in integral rotation (single control) themovement of the unit drum of the indicator-counter of the frequency andthe movement of the condensers of heterodyne l and of the filter changerblocks I i0 and I6, theother, the displacements of the heterodynecondensers and blocks, the reversals of running of the condensers, thequartz oscillator and aerial commutators, the numeral drums of thefrequency indicator-counter and all manipulations appertaining to thepassage from one section to another. Of these handles, the first has acontinuous movement and theY second has an interrupted movement and canfix itself on nine different positionsv (one per section).

Direction table'per section lst block HF 250-750 kc. 2nd block HF750-2500 kc.

Wage re- D. H t y A Y Tapylnliing oil ceive range is- Dire@ e DisplceDirec aeria ena Range ptllaecleg tion 325i-:025 Range ment tion Qtz.

250-500 250-500 0 For. For. lst lter. 500-750 G-750 90 750-l,000 50G-25090 Rev Rev 7501,000 2nd ltcr. l 000-1, 200 750-500 0 1, 000-1, 250 1,250-1, 500 50G-250 90 1, 250-l, 500 1 500-1, 750 250-500 0 For. For.' 1,50G-1, 750 l '1250-2,000 500-750 90 1,750-2,000 2, 000-2, 250 250-500 02, OOO-2, 250 2, 250-2, 500.. 500-750 90 2, 250-2, 500

Of the above values, (l) is controlled by the members of the lstdifferential, (2) and (3) are controlled by the members of the directionreverser, (4) is controlled by the members-of the 2nd differential, (5)is controlled by the members of the quartz reverser and (6) iscontrolled by the members of the aerial tapping.

The two categories of controls to which respectively the twofhandlesareallocated, are indicated in a general way on Figure l, the rst by dottedDetailed examination of the above table shows ferential at the rate oftwo and a half revolutions per section; secondly, acts on the adjustmentof the condensers of the lst and 2nd lter changer block effected by thesingle control, according to the above table, these adjustments beingeffected by the displacement of the connecting members of thedifferentials 25 and 25; thirdly, actuates the direction reversers ofthe condensers of the filter changer blocks I and I5; fourthly, actuatesthe reversers of the quartz oscillator of the heterodyne 22; and fifthlymanipulates the aerial commutator I5.

These multiple operations are ensured by the intermediary of a drumselector, illustrated in Figure 2.

As shown in this gure, the selector comprises a drum 38 provided withindentations of different depths or widths into which penetrate thenoses of a number of levers or pawls 3 I, 32, 33, 34. Each of theselevers actuates a rod system 35, 38, 31,

38. The rod systems 35, 36 act on the differentials 25, 2G to effect theadjustment of the variable condensers of the filters. The rod systems31, 38 cause the movement of the aerial commutation members, of thequartz oscillators and of the reversal of the lter condensers.

' tion of the drum 38 towards its new position. The

lever 43 also drives a rod system 45, the function of which is to lockthe adjustable members of the diiferentials when they have been broughtinto their approximate position by the rod systems 35, 36.

Furthermore, by means of a retarding member (which may for example, beof the clockwork or dash-pot type) the pawl 44 is kept for a suitabletime in the set position, after the return of the cam 42. This permitsof avoiding the manipulation of the members for all the intermediatepositions between two non-adjacent sections.

Thus, when the section is changed, the manipulations are as follows:1st, the unlocking of the differentials; 2nd, setting of the levers crpawls; 3rd, rotation of the drum; 4th, freeing of the pawls; 5th,locking of the differentials.

Figures 3 and 4 show in plan View the position of the parts shown inFigure 2 in the phase of rotation of the drum (Figure 3) and in thephase of operation of the receiver (Figure 4) Figure 5 illustrates aconventional representation of the entirety of the elements 01" themechanical controls of the system.

Figure 5 shows the selector drum 38 operated through the spindle 39 bythe Maltese cross 40, the cam 42, the pawls or catches 3|, the lever 45and the rod or pawl 44. Connected to the locking rod system 45 are aretarding device 45 constituted by a dash-pot, a resetting spring 47,locking pieces 48, 49 constituted by levers hinged at one of theirextremities to the rod 45 and carrying at the other extremity rollers59, 5I engaging in notches 52, 53, 54, 55 on the adjustable elements ofthe differentials 28, 25, through the intermediary of which are driventhe variable condensers 58, 53 of the lters of the frequencyselectorchanger blocks I and I5.

The lever or pawl 3I is connected to the rod 35, which in turn operates,through a toothed sector 60, the displacement of the differential 25driving the variable condensers 59 of the rst lter changer block I. Are-setting spring 5I draws the lever or pawl towards the drum. A similaroperating movement is constituted by the rod 36, actuated by the leveror pawl 32 (not shown in Figure 5), which operates through thedifferential 25 and a sector 62 and against the action of a spring 63,the displacement manipulation of the condensers 58 of the second lterchanger block I6.

The commutation rod system 3T effects either the reversal of directionof rotation or the reversal of variation of the capacities for the samedirection of rotation of the variable condensers of the heterodyne I andof the lter block I. This result is obtained by the play of twocommutators 64 and 65 putting into operation one or the other of twosymmetrical stators with which these condensers are provided. A spring68 draws the rod 31 back to starting position.

By means of a similar mechanism the rod 38 actuates the commuator 23 ofthe quartz oscillators Q1 and Q2 of the heterodyne 22 and the rod 81 thecommutator I5 of the aerial I4.

There will now be described the detail of the connections operating thecontinuous movement control. The spindle 68 of this control, upon whichis keyed a handwheel 69, drives by a helicoidal worm 'I an intermediatespindle II which, by means of a tangent worm 12, drives the spindle 'I3of a variable condenser I4 of the heterodyne 1. There is also keyed onthe spindle 58 a pinion 'I5 which, through a train of toothed wheels 16,11, 18, drives the elements of the differentials 2B, 25 with which thereare integral in rotation the filter condensers 58, 59.

The spindle 7l, through the gears 18', 11', 18', drives the drum I9(unit drum) of a drum counter 80. To obtain a transmission without play,the intermediate gear I'I is applied against the other gears by means ofa compensator spring 88.

The ratios of reduction of these different controls are as follows: fora half turn of the variable condenser 14 of the heterodyne 1, thecondensers 59 of the first filter changer block I rotate by 1/4 of arevolution, those of the second block I6 rotate by 1/14 of a revolutionand the drum 'I9 of the units of the frequency indicatorcounter rotatesby 25 revolutions.

The ratio of reduction between the movement of the condensers 59 and 58as also the angles of fixation of the latter condenser, may be easilydeduced from the general formulae given at the beginning of thedescription.

Actually, the condenser 58 is supposed to cover in one-half revolutionthe frequencies from '750 kc. to 2500 kc. There is thus obtained: for

and for a1=rr F10=2500 These two particular values applied to theEquation 2 give for k1 the Value:

a0=1r Fo1=750 whence according to the Equation l the ratio of reductionm given for the Formula '7 is thus:

ko (l0) For the third line:

'For the fourth and fth lines:

In the counter 30, between the drum 8| of the tens and the drum 19 ofthe units, there is interposed, in addition to the normal connectionmechanism from drum to drum according to the counter or meter system, aconnection through a differential 82, permitting of eifecting adisplacement corresponding to two and a half revolutions for each changeof section (corresponding to 250 Vkilcocycles). The displacement of thedifferential 82, starting with the movement of the primary spindle 3S ofthe interrupted control, is transmitted by spindles 83, 84 vand toothedwheels 85,

, 86 and 87.

As regards the heterodyne block I, all useful constructional precautionsshould be taken to ensure its accuracy; in particular the variablecondenser, the self-inductance and the bulb of the oscillator valve,should or may be mounted in a copper box forming an hermetic seal, whichbox itself may be mounted on the front panel of the receiver. To ensurethe greatest possible constancy with reference to the temperature, the-variable condenser should or may be constructed of metal, the coeicientof expansion of which varies very little as a function of thetemperature. Even then, the frequency is not rendered entirelyindependent of temperature; there is still a separation, which, however,can be reduced by about 70% by using condensers having a negativetemperature coefficient, which annuls the separation in the centre ofthe range in question. In place 0f such compensation, there may beutilised two bimetallic strips r89, 9D as reading index, one of thesestrips being utilised for running in one direction and the other forrunning in the opposite direction.

The means employed to obtain the reversal of the relative direction ofvariation of the capacity vof the condensers (that is to say, thecondensers of the precision heterodyne l and condensers of the lter i)for the same direction of rotation of the rotors, consists in utilisingcondensers of the type with two symmetrical stators, placed in usealternately and automatically by the action of the commutators 65, 64.

These condensers are, furthermore, of `a type with linear variation offrequency; preferably, there will be provided for the condenser 0f theprecision heterodyne 1, the kind of condenser of this type in which thedesired linear law of variation results from the prole of the blades,and for the condensers of the filter l, those of the kind in which thedesired linear law is obtained by the interposing of a cam of suitableprole between the actuating spindle and the spindle of the rotor of thesaid condenser. This system permits of obtaining, with the desiredlinear law, a more extended ratio between the maximum frequency and theminimum frequency, an extension necessitated by the development of rangeof the filter I.

While the basic principles of the invention in its widest scope havebeen clearly set forth in the preceding description, it remains todescribe briefly, as illustrated in Figures 6-10, certain arrangementswhich will aid in understanding the application of the invention to avery wide range of frequencies and which will enable an easiermanipulation of the control in the Wide system, which latter' can makeuse of servo-motors.

The invention may be carried into effect in various ways.

One embodiment will be hereinafter described, by way of non-restrictiveexample, as applied to the construction of a receiver, said embodimentincluding numerical values in order that the example may be fullyillustrative.

In a general way, in apparatuses of the type in question in thisinvention, the reading of the frequency takes place on a cyclometercounter, the total range of the apparatus being divided into sections,each covering the same number of kilocycles, and a direct variation offrequency of the resonant circuits being maintained proportionately tothe variation of position of the control member.

The frequency is determined by means of two manipulations. The firstenables the selection of the section containing the frequency to bereceived; it actuates the elements of the counter indicating the numberof hundreds of kilocycles and a set of combining members which preparesthe necessary combinations. The latter are executed when the selectedsection is engaged.

The second manipulation serves to travel over the section; it thereforecontrols the variable frequency Aheterodyne of the last change offrequency and operates, in the counter, the wheels of the tens and ofthe units.

Assume a total range of from 100 to 24,300 kilocycles, this range beingdivided into sections of 100 kc.

The high frequency portion comprises (Figure 6) ve blocks I, II, III,IV, V of identical design, differing only by their range of frequency.They are used in progression according to the frequency to be received.

For the lowest frequencies (100-300 kc.) only 13 block I is used; thisblock in conjunction with a variable heterodyne I-I supplies to theamplifier MF the oscillations having a mean frequency of 50 kc., whichsupply the amplifier detector BF; for higher frequencies (300-900 kc.)blocks I and II are utilised.

The block II transposes the frequency which it receives by utilisingquartz oscillators and delivers under these conditions at its output,when the signal frequency varies, a variable intermediate frequencywhich covers the range of the block I.

The receiver then behaves as a receiver with double frequency change,the first mean frequency servo-motor |06 and it is integral with acontact disc formed in two parts |01, |01 with a slot |08 between theparts. Brushes |09, |09', |09" etc., bear on the contact disc. The motoris supplied with electric current from a source ||0 (Figure 9b),indicated by its two poles iand The terminals of the motor are connectedrespectively to the brushes |09" and |09"", and, through resistancesIII, H2, to one of the poles of the source H0. The other pole of thesource HU is connected to the brushes |09, |09 and |09 through contactsH3, H3', and H3, of the section combine. The making of one of thesecontacts, for example the .contact H3, causes of which is variable andthe second is fixed. the setting in rotation of the motor in the de- Forstill higher frequencies (900-2700 kc.) sired direction, the rotation ofthe motorcontinublock III comes into operation and, by the same inguntil the slot |08 comes opposite the brush procedure, supplies avariable intermediate fre- |09. At this moment, the motor stops, thecrown quency covering the range of the block II. The having undergone adisplacement equal to the receiver is then of triple frequency change.angular distance between the brushes |09', |09". The reception of stillhigher frequencies neces- The closing of the contact I3 would havecaused sitates the placing into service of supplementary the placing inrotation of the motor in the opblocks IV, V, in the example shown.posite direction until the arrival of the slot |08 The following tableshows the ranges correopposite the brush |09. sponding to the placing inseries of the different There is thus obtained, by a simple electricalblocks: control, the displacement of the differentials, the

Table Wave to be received No. of

Intake from High frequency sections aerial blocks used of 100 kc. F.,kcs. Meters 10o- 300 aoco-1,000 Block I 2 c- 900 1,000- 333 mock n-.. e900- 2,700 a33- 111 mock 111. is 2,700- s,1oc 111- 37 Blockiv-- 54 s,10o-24, 30o 37- 12.4 Block v-.. 162

Each high frequency block comprises three tuned cicuits of variablefrequency covering` a range of ratio 3, an amplifier valve and a mixervalve.

The following component members are utilized.

1. Reduction and adjustment The condensers of direct variation offrequency are controlled from a single manipulation (manipulation of thevariable heterodyne condenser) in such a manner that the condensersappertaining to a block of higher index move three times as slow as thecondensers of the block of lower index immediately adjacent.

On the other hand, according to the sub-range selected, the adjustmentof the condensers of one block with respect to those of the blockimmediately adjacent must have a well defined value. v

These two conditions are obtained by differentials, which are insertedbetween the controls of the dilerent blocks according to thediagrammatic arrangement of Figure '77, which is self-explanatory. Theadjustment takes place by putting into a definite yposition thesatellite-carrying crown of the differential. According to the presentinvention, this operation is carried out by a small servo-motor rotatingautomatically just the amount necessary to bring the crown to thedesired adjustment, see Fig. 9.

The said mechanism comprises a differential lill, having a reductionratio of 1:3, coupling the shaft |02 of the lower block with the shaft|03 of the upper block, the crown of the differential being marked |04and the satellites carried thereon |05. The crown |04 is in engagementwith a manipulation of the section combiner being limited to effectingcontacts, with consequent elimination of the mechanical eiortsnecessitated by a direct control.

2. Reversal of direction To obtain maximum efficiency in the use of theapparatus, it is necessary to utilise in the successive changes offrequency, sometimes the upper beat and sometimes the lov/er beat. It isthus necessary that the variation of the capacity of certain blocksshould be an increase for certain sections and a decrease for others.This result is obtained by providing, on each block, not simply a singleset of condensers but two sets controlled in opposite directions and byselecting, according to the section, that one of the two which issuitable.

Such an arrangement is obtained, according to the present invention, inthe manner shown in Figure 8, the part (a) of which illustrates themechanism employed and the part (D) the electrical diagram. Themechanism referred to comprises two condensers |253, |2|, which may forexample, be of the type having sliding armatures, in which case theyhave three sets of armatures. The armatures o1' these condensers arecontrolled by cams W2, |23. The cams Iii?, |23 are keyed on to the shaftmechanically connecting the differential of the block N to which thecondensers in question appertain, to the differential of the blockimmediately above (N+1). r`iheir profile is so chosen that the variationof frequency is in direct relation to the rotation of the shaft, Thecams are reversed one with respect to the other in order to obtain thereversal of the law of variation. The operation in forward or in reversedi- 15 rection results, as shown by Figure 8o from the position of theswitche 226;, |24', |24" appertaining respectively to the sets ofarmatures, these switches being connected by the section combiner.

3. Frequency of conversion The value of the frequency utilised for theconversion is one or the other of two fixed values given by quartzoscillators, the frequency of which has or has not been multiplied.

In the present example, the carrying out of the range necessitates eightquartz oscillators, arranged two for each block and distributedaccording to the following table:

Table No. of the block II III IV V Kc. Kc. Kc. Kc. Frequency of lstquartz oscillatolz." 500 1,500 4, 500 13, :TO Frequency of 2d quartz0scillator 700 2, l0() 6, 30|) 18, 9U() These dilferent frequencies maybe obtained from the two quartz oscillators of 500 and 700 kc.respectively by several times tripling the frequency: if need be, asingle quarts oscillator of 1GO kc. may be started with. The latterarrangement permits of the maximum of precision over the whole range.

Only block uses the frequency of a continuous range heterodyne H ofratio 5:3 and the two beats of which are taken; it constitutes the highfrequency part of the normal receiver.

4. Combiner As has been remarked with respect to the con-` trol of thevariable condensers, the combiners of each block are controlled by asingle manipulation by the section-changing handle which directlyactuates the counter, in such a manner that the combiner allocated to ablock of higher index changes three times less than the precedingcombiner.

This condition is carried out, according to the present invention, byMaltese crosses of ratio 3 which are inserted between the controls ofthe combiners of the different blocks. Figure shows the generaloperation of the combiners. The section handle |3 directly operates thespindle of the switches allocated to the block I. These switches aredistributed in four series, shown diagrammatically in the form of fourdiscs |3|, |32, |33, |34 with three positions of contact. These discsinsure respectively the four functions enumerated above under (a) to(d). Other discs may be provided, either to subdivide the operations orto insure supplementary operations allocated to each block. Through theintermediary of the Maltese cross connection |35, |36, the spindle ofthe switches of the block I drives the spindle of the switches of theblock II in such a manner that for one revolution of the first spindle,the second is shifted by a third of a revolution, and so on from onespindle to the next. The method of operation fromv the section handle ofthe counter drums has not been shown. There may tbe used to this end,the embodiment described hereinbefore. There may also be used aservo-motor drive of the type used in the arrangement of Figure 9. Thesame type of control could, furthermore, be used in place of Maltesecross systems in the connections between the spindles of the switches ofblocks I to V thus eliminating any motive effort to be supplied by thesection handle |36.

The remainder of the receiver comprises (see Fig. 6) the usual elementsof an amplifier, mean frequency filter MF on 50 kc., low frequency BF,and supply R.

What I claim is:

l. Apparatus for the interconversion of frequencies between two rangesthereof, one being an extended range including higher frequencies (F1)and the other being a fraction of the first mentioned range andincluding lower frequencies (Fo) comprising oscillator means having acommutator, for the generation of at least two fixed frequencies (Fq),so chosen that there can be a transformation, by combination with one ofthe fixed frequencies with each frequency of one range, of eachfrequency of a range into a frequency of the other range, meansincluding commutators for effecting tuning on each section correspondingto a portion of the range of higher frequencies, means includingcommutators for tuning on the range of lower frequencies, means foreffecting coupling between the first mentioned and second mentionedtuning means and the commutator of said oscillator producing the saidfixed frequencies, said coupling means being constructed and arranged sothat the said higher and lower frequency ranges are each covered in itstotality and in a continuous manner by one or more tuning devicesvariable linearly with frequency, said coupling between tuning devicesfor the lower and the higher frequencies comprising demultiplicationmeans, whereby under control of the tuning devices the frequencies tunedin the higher and lower frequency ranges are changed by a like absolutevalue, and an adjusting means which on passing to another section of therange of the higher frequencies enables the adjustment by apredetermined amount of the tuning means for the higher `frequency rangerelative to that of the lower range.

2. Apparatus according to claim l wherein the said adjusting meanscomprises a differential device having central planetary wheels and acage carrying cooperating satellites, the said central planetary wheelsbeing connected respectively to the tuning devices of the lower andhigher frequency ranges and including means for effecting changeover tothe different sections of high frequency range, said changeover meanscontrolling said cage.

3. Apparatus according to claim 1 including a control device having acontinuous movement for controlling simultaneously the tuning device ofthe lower and higher frequency ranges, a controlling device having adiscontinuous movement and having a distinct position for each sectionof the high frequency range and comprising a number of levers, a drumwith intermittent rotary movement for controlling the position of saidlevers, means by which one lever controls the adjusting means, a secondlever switches the REFERENCES CITED The following references are ofrecord in the iile of this patent:

UNITED STATES PATENTS Number Name Date Lear Dec. 21, 1937 Lowell Jan.16, 1940 Banfield Sept. 24, 1940 Carlson June 10, 1941 Brandholt Sept.29, 1942 Gendriess Feb. 16, 1943 Swallow Jan. 2, 1945 Dimmer June 26,1945

